Since the introduction of computed tomography (CT) in the early 1970s, x-ray based tomographic imaging has become a fundamental tool employed in nearly all areas of medicine, including cancer screening and research. SRI International is developing a new stationary x-ray source with the potential to revolutionize tomographic imaging technology. The possibility for increased imaging speed and the implementation of novel acquisition geometries imparted by such a source could lead to the development of compact, affordable CT and digital tomosynthesis systems for use in hospitals, clinics, rural areas, and laboratories, and thereby benefit both the medical care and research fields. We have investigated the physical principles underlying a new stationary x-ray source approach based on microfabricated cold cathode technology. Our studies have demonstrated the potential of the stationary source to provide the flux and fluence required by many medical imaging applications. These earlier studies focused on investigating the x-ray production characteristics (x-ray flux, fluence, and focal spot size) of the individual x- ray source elements that would be grouped to form the stationary source. Here we propose to demonstrate the utility of the stationary source for medical imaging, in terms of x-ray emission characteristics and reliability, with a fully functional stationary source. The stationary source will be applied to digital tomosynthesis imaging of small animals, as this is a reasonably straightforward implementation of tomographic imaging for our prototyping studies. Although directed toward small animal imaging, the results of the stationary source studies will be applicable to other DT systems, such as those under investigation for human breast imaging. The specific aims of this R21 proposal are to: 1) construct a stationary x-ray source and source evaluation testbed and 2) use this testbed to evaluate performance of the stationary x-ray source. The successful completion of the proposed study will expedite development of this new stationary x-ray source approach and could result in an arguably revolutionary improvement in x-ray source technology for tomographic medical imaging systems. PUBLIC HEALTH RELEVANCE: We propose to significantly improve medical imaging technology by developing an x-ray imaging system that will allow cancer researchers to take three-dimensional x-ray motion pictures. The potential for increased imaging speed, reduced system cost, and the implementation of novel acquisition geometries imparted by such a device could lead to the development of compact, affordable CT and digital tomosynthesis systems for use in hospitals, clinics, rural areas, and laboratories, and thereby benefit both the medical care and research fields.